The present teachings are predicated upon providing an improved method of making one or more components of a brake system. Brake systems are used to decelerate and/or maintain in a stopped or parked position a vehicle, such as a car, truck, bus, train, airplane, or the like. Alternatively, brake systems may be used with equipment requiring a brake, such as a lathe, a wind turbine, a winder for paper products or cloth, amusement park rides, or the like.
A typical disc brake system generally includes a brake rotor, a caliper body, a support bracket, an inboard brake pad, and an outboard brake pad. The caliper body generally, includes one or more fingers, and one or more piston bores each supporting a brake piston. During a brake apply, fluid is pressurized causing at least one of the brake pistons to move the inboard brake pad towards a side of the brake rotor. Simultaneously, or slightly thereafter, either the one or more fingers pull or another brake piston pushes the outboard brake pad towards an opposing side of the brake rotor. In this regard, both the inboard and outboard brake pads are forced against the brake rotor to create a friction force that is sufficient to reduce the rotational speed of the brake rotor. Accordingly, the vehicle can be decelerated and/or maintained in a stopped or parked position.
Typically, one or more components of the disc brake system are made via a casting process, and, typically, the components are cast individually. That is, for example, the caliper bodies are usually cast on a dedicated caliper body casting line using one set of dedicated tools, and the support brackets are usually cast on another dedicated support bracket casting line using another set of dedicated tools. The cast caliper bodies are then trimmed and cleaned, and excess cast material is removed, all of which takes places on a dedicated caliper body trimming line. Likewise, after casting, the support brackets are trimmed and cleaned, and excess cast material is removed, all of which takes places on a dedicated support bracket trimming line. After cleaning the caliper body and the support bracket are machined and controlled on separate lines, with separate setups, and separate tools and fixtures. During each of the machining operations, one or more corresponding features, such as pin bores for example, are machined in the caliper body and in the support bracket for assembling the caliper body and support bracket.
After the respective machining operations, the caliper bodies and support brackets are assembled along with other components into a brake system. However, as a result of separate marching operations, variations in the machining processes may make assembly difficult, or affect performance of the brake system in a negative way. For example, if the bores or other corresponding features in the caliper body and support bracket are not properly aligned, it may be difficult to assemble the caliper body and support bracket. Accordingly, one or both of the caliper body and the support bracket may need to be reworked or, undesirably, scrapped, which may disrupt the assembly process and add additional time and cost to the process. While increasing the tolerance limits of these features may help ensure that these components fit together during assembly, larger tolerance limits may adversely effect performance during functioning. For example, increased tolerance limits may cause movement of the components, which may undesirably result in disc thickness variation (DTV), brake torque variation (BTV), high noise levels, or other effects. Such movement may also undesirably reduce the life of the brake pads, the brake rotor, or both, and may have an adverse effect on fuel efficiency of the vehicle.
Accordingly, it may be desirable to have components for a brake system with corresponding features, such as pin bores having an improved alignment, and a method of making the same. It may be attractive to have a method of casting two or more components of a brake system using one set of casting tools (e.g., patterns, core boxes, etc.). It may be desirable to have a method of casting a caliper body and a support bracket using a single core. It may be desirable to have a method of making a caliper body and support bracket, where the parts are cast together, and then together trimmed and machined. Accordingly, the number of tools and the number of operations required to create the caliper body and the support bracket may thus be reduced; the pin bores in the caliper body and the corresponding bores in support bracket may be better aligned; or both. It may be attractive to have a method of making a caliper body and support bracket where variations in the concentricity of the bores in the caliper body and in the support bracket are reduced so that assembly of the caliper body and support bracket can be improved and thus scrap and/or components requiring reworking can be reduced. It may be attractive to have a method where the dimensional relationships between functional features in the caliper body and the support bracket are tightly controlled by machining the two components together as one piece.